Website speed: how it affects sales

How does a slow website reduce sales?

Visitors do not come to your website to wait for the server. They want to see a price, availability, phone number or delivery method. If the main content appears too late, some people close the page. If a button moves while the page is loading or a form responds slowly, others give up-even if they have already decided to get in touch.

The problem is most apparent with mobile visitors and paid campaigns. Someone who arrives from an ad for a specific product or service expects to see that exact offer. If a banner, chat, tracker, video and several heavy scripts load first, you are paying for a visit that may never reach the content.

For an online store, losses can occur after the product page as well. A slow filter, search function, cart or checkout interrupts the path to an order. External API connections to a courier, payment provider, warehouse or ERP also need to be checked, because a fast homepage does not mean a fast store.

There is no honest universal formula such as “one second of delay means exactly a certain percentage fewer sales”. The result depends on the price, level of trust, traffic source, device and order complexity. Compare technical data with submitted forms, calls, completed orders, abandoned carts and conversion by device.

What should you measure besides the PageSpeed score?

Google PageSpeed Insights is useful for diagnostics, but its score is not a business goal. A website can have a high score and an inconvenient checkout. Another may have a lower score but display the offer quickly and generate more qualified enquiries.

Core Web Vitals show how the page loads and responds for real visitors. Track them separately for mobile devices and desktop:

In Search Console, real-user data can reveal a problem that a lab test misses. An office computer with a fast connection may produce a good result, while customers on a mobile network wait too long.

Other metrics are also important for the business: started and completed orders, submitted forms, clicks on phone numbers, abandoned carts and results by device. For advertising, connect the data to the specific campaign and landing page. For a B2B website, check whether the slow page is reducing enquiries in the CRM.

Which problems most often slow down a website?

Large and improperly prepared images

A photo from a phone or camera is often larger than necessary for the specific screen. Prepare an appropriate size and format such as WebP or AVIF. Set the width and height so the elements do not shift, and use lazy loading for images below the fold.

The hero image is an exception. If it is the main LCP element, it should not automatically be deferred. It needs to be prepared correctly and loaded with the appropriate priority.

Unnecessary JavaScript and plugins

A chat widget, pixel, map, animation, pop-up and external tracker can gradually put a strain on every page. In WordPress, the problem is not just the number of plugins. What matters is what they load, on which URLs they load it and whether they are up to date.

Do not remove a feature simply because it looks unnecessary. You could stop a form, conversion tracking, payment or CRM connection from working. Investigate the script, check its dependencies and load it after the main content when it is safe to do so.

Slow server and missing cache

If the server is slow to return the initial response, compressing images will not solve everything. The cause may be overloaded shared hosting, inefficient database queries, missing server-side caching or an unsuitable configuration.

Cloudflare can help with CDN, caching, DNS and protection, especially for static content. It will not fix heavy JavaScript, slow database queries or an incorrectly cached dynamic cart. Before changing hosting, identify exactly where the time is being spent.

Third-party services that block loading

Advertising scripts, analytics, chat, video and fonts from external domains add requests. Sometimes they block the main content. Load them after the essential content, but do not delay a script required for cookie consent, payment or security without checking the consequences.

Complex logic in an online store

Filters, search, customer group pricing, inventory, couriers and cash on delivery often require database queries and external APIs. Test the entire journey, from searching for a product to order confirmation, not just the homepage.

How to check your website speed before paying for changes?

1. 01
   Choose real-world scenarios

   Record the pages that generate the most traffic or revenue. For a store, include a category, product page, cart and checkout. For a B2B website, add a key service, the contact page and the enquiry form.

2. 02
   Test from more than one location

   Use Google PageSpeed Insights for lab and real-world data. If needed, add GTmetrix or WebPageTest for waterfall analysis. Check both mobile and desktop versions, and do not treat a single test as a definitive diagnosis.

3. 03
   Connect technical data to the business

   Compare the results with Analytics, advertising campaigns and CRM. If a mobile campaign generates visits but few form submissions, check the specific landing page, form and scripts, not just the homepage.

4. 04
   Prioritise changes by impact and risk

   Image compression, proper caching and removing unnecessary scripts are often a more sensible first step than changing the entire platform. For every change, clarify what could break.

5. 05
   Measure again after publishing

   Test the same URLs, devices and actions. Check forms, payments, advertising events, SEO URLs and integrations with ERP or CRM. Otherwise, you may get a greener score but fewer enquiries.

How much does it cost to speed up a website?

The price depends on the platform, access to the code and server, the number of templates, integrations and whether the website must remain operational during the changes. For a technical audit or specific optimisation without a separate pricing package, the price is “stated in the proposal”.

For a new development, the price within the range above depends on the number of templates and screens, design complexity, content migration, integrations and admin panel requirements. For a store, adding customer-specific pricing, inventory, couriers, payments and an ERP connection increases the scope.

Hosting is a separate expense. A quality shared plan may be sufficient for a small corporate website. A busy store or a system with specific requirements may need a VPS, a separate database, backups and monitoring. See what hosting includes before comparing only the monthly fee.

When is optimisation not enough?

Sometimes a website is built on a theme with too many features, an outdated version of PHP, an unsuitable database or an architecture that makes every page dynamic. A few settings may help temporarily, but they will not solve the problem as traffic or catalogue complexity increases.

A redesign makes sense when slow technology is combined with poor structure, an inconvenient mobile checkout or a lack of tracking. The new development should begin with measurable scenarios: time to a visible offer, search, filtering, form submission and order completion.

For an online store, this can be planned together with online store development, rather than as a cosmetic change to the homepage. For a company website, first check whether the problem is limited to a specific service or landing page. Sometimes a narrower scope delivers better results than a complete redesign.

Speed is also part of the technical side of SEO optimization, but it should not be considered separately from the content, search intent, structure and conversions.

What should you ask your developer for?

Do not just ask for “a PageSpeed score above 90”. Ask for a list of the specific causes, the affected pages, the measurement method and the risk associated with each change. A good proposal specifies whether the work will involve images, JavaScript, caching, the database, hosting or external integrations.

Also clarify what will not be changed: advertising events, forms, payments, SEO URLs, schema data and connections with ERP or CRM. After publishing, ask for a repeat test and a brief report, not just a screenshot of a green score.

Maintenance is also part of speed. A new plugin, product image, advertising script or theme change can worsen the results again. For a website that changes frequently, website maintenance is more predictable than repeatedly putting out fires.